1. Field of the Invention
The present invention relates to an injection valve, in particular for fuel injection systems of internal combustion engines of motor vehicles.
2. Description of Related Art
A known injection valve for fuel-injection systems for internal combustion engines described in published German patent document DE 42 30 376 has a valve-seat support in which a valve-seat body is inserted at the extremity. The valve opening and the valve seat surrounding the valve opening are formed on the valve-seat body. The hollow-cylindrical valve needle is open at one needle end for the entry of fuel, and other needle end is sealed by a spherical valve-closure member, which is welded onto the valve needle and provided with radial exit holes for the fuel. The valve-seat support is affixed on the hollow-cylindrical solenoid core via an intermediate piece, by welding, for instance. Opposite the hollow-cylindrical magnetic core, forming a working air gap, is the magnetic armature, which is integrally formed with and situated on the valve needle. The valve needle is guided in the intermediate piece via its magnetic armature in an axially displaceable manner. The solenoid coil, made up of a coil body and an excitation winding wound inside the coil body, is slipped over the solenoid core. The excitation winding is connected to a connector plug. The end of the solenoid core facing away from the magnetic armature is formed as connection piece for the fuel-supply line, in which a fuel filter is inserted. The solenoid coil is surrounded by a ferromagnetic conductive element having the form of a bracket, which rests against the solenoid core via its one end and against the valve-seat support via its other end and is joined thereto by welding or soldering, for example. Solenoid core, solenoid coil having ferromagnetic conductive element, and valve-seat support are enclosed by a plastic-extrusion coat in which the connector plug is integrated. The valve needle is produced with the aid of so-called MIM technology (metal injection molding), by injection molding and subsequent sintering. The valve needle is injection-molded from a metal powder having an adhesive agent, such as a plastic adhesive agent. The adhesive agent is removed again by sintering. The sleeve-shaped or cylindrical valve needle produced in this manner, in which the exit holes are already formed and the solenoid core is premolded, is joined to the spherical valve-closure member via its end face, by welding.